The nanochannel fabrication method using PDMS and AFM tip-based process is actually a very interesting method. Even though AFM tip has a different purpose conventionally, using it as a fabrication technique in nano-domain is attractive. From the provided AFM images of the nanochannels, the quality of the channel walls and distribution of the sizes are acceptable. One concern using this technique is the even though the sub-100 nm channel depths are achievable, it is hard to control the channel width in the same range, thus the milled nanochannels are more suitable to call as nanoslits (in the range from 400 to 800 nm). So for a case that requires nanochannels of the size less than 200 nm this method may not be suitable. It also requires the fabrication steps to heavily depend on the controlling the voltages of the actuators thus may cause issues to control the size of the nanochannels. Additionally the PDMS ratio should be heavily controlled to get the desired channel dimensions and ratios.